Brush rigging for electrical apparatus



y 1942- G. A. BRETTELL, JR

BRUSH R IGGING FOR ELECTRICAL APPARATUS Filed May 8, 1941 2 Sheets-Sheet l ATTOR y 1942- G. A. BRETTELL, JR 2,282,450

BRUSH RIGGING FOR ELECTRICAL APPARATUS Filed May 8, 1941 2 Sheets-Sheet 2 BY 6 izfw ATTORNEY Patented May 12, 1942 f BRUSH RIGGING FOR ELECTRICAL APPARATUS George Alvin Brettell, Jr., Newark, N. J., assignor to American Transformer Company, Newark,

Application May 8, 1941, Serial No. 392,457

12 Claims.

This invention relates to a brush rigging for electrical apparatus, some portion of which has relative movement under and in contact with brushes carried by the rigging. The structure of the invention is especially adapted for use in connection with a voltage regulator such as shown and described in Schermerhorn Patent 2,089,434, issued August 10, 1937.

While I have chosen to illustrate my improved brush rigging with such a structure as generally illustrated in the Schermerhorn patent, it may be used with other types of electrical apparatus requiring brushes.

One of the objects of my improved form of brush rigging comprises an arrangement in which a plurality of brushes may be individually mounted on a common stud, the brushes themselves being self-aligning in a direction along the length of a commutator bar or conductor adapted to be engaged by the brushes, thereby producing a better and more effective result than a single, wide brush.

Another object of my invention is to provide a mounting for each individual brush unit which will provide the maximum area of brush contact on a commutator bar or conductor during any relative shifting operation between the bar or conductor and the brush.

Another object of my invention is to provide a brush unit which, while guided by a supporting stud, is actually pivoted on the commutator or conductor surface over which the brush operates.

Another object of my invention is to provide a brush rigging in which the individual brush units are quickly and easily assembled to the supporting and guiding stud.

Another object of my invention is to provide a brush rigging in which the parts are spaced so as to provide good heat radiation.

These and other objects will be discerned by one skilled in this art from a reading of the specification taken in connection with the annexed drawings, wherein:

Figure 1 is a partial plan view of my improved brush rigging as applied to a voltage regulator of the Schermerhorn type.

Figure 2 is a view on the line 22 of Figure 1.

Figure 3 is an end view of Figure 1, looking from the bottom of the View toward the top.

Figure 4 is a view on the line 4-4 of Figure 1.

Figure 5 is a view similar to Figure 4, with one of the brush units slightly raised laterally to indicate in an exaggerated manner that the brushes of this unit have not worn down the track as fast as the brushes of another unit, although this condition may never happen.

Figure 6 is a view of the brush unit per se illustrating the long pivotal action of the brushes on the commutator bars or conductors when one is a little high, the drawing being exaggerated to show this.

Figure '7 is a fragmentary View showing how any one of the brushes may automatically swivel on its support.

' Figure 8 is the same as Figure '7, but with the brush in its usual operative position.

Figure 9 illustrates, diagrammatically, certain conditions which may be brought about by the use of a conventional type of brush holder, especially where the brush rigging itself is rotated about the peripheral surface 'of a regulator of the type heretofore referred to, the diagram at illustrating one condition, and diagrams b and 0 illustrating two other conditions to which reference will be later made.

In the drawings, wherein like numbers refer to corresponding parts in the various views, I illustrates'the windings on a ring-type transformer having any type of satisfactory core. The

outer peripheral surface of the conductors of the Winding l is bared and turned down to provide a smooth surface 2 similar to that on a commutator on a D. C. machine. As illustrated in Figures 1 and 2, the brush contact surface 2 is positioned between the bands 3 and 4 which are suitably insulated from the conductors of the winding I and which may form collector or distributor rings for the current conveyed by the brushes. The rings or bands 3 and 4 may be constructed by winding heavy conductors, preferably of copper, around the opposite ends of the apparatus and then machining them down to a smooth surface, or the bands may be a single, integral piece. So far as the winding, its core and other regulator parts are concerned, no further description is necessary.

Coming now to the details of my invention, a metallic stud 5, which may be of steel treated to prevent rusting, as by parkerizing, forms a part of the brush rigging and is carried by an operating arm 6, but insulated therefrom by suitable insulators. The supporting stud 5 is provided with a plurality of grooves 1 to receive brush units each composed of a metal plate 8 having slots or notches 9 therein to fit over a reduced portion ll] of the stud 5. The plate 8 has its opposite ends II and I2 bent in the same direction to form supports. On the support end H is mounted a brush l3 carried in a U-shaped metallic holder l4, both being fastened to the support lug H by a stud I5 having nuts 16 and I1 engaging its oppositely threaded ends. A washer I8 is used on the outer surface of the holder 14 and has a thickness cooperating with the outer threaded end of the stud i5, so that when the nut It is tightened up against the shoulder portion of the stud, the brush with its holder is gripped to a degree such that the holder and brush may swivel on the stud somewhat as indicated in Figure 7, so that the end of the brush will come into straight alignment with the bars or conductors on the surface 2.

Each brush is provided with a pigtail i9 of stranded copper wire, and to the end of the pigtail is attached a terminal 2%! adapted to be clamped by a nut 21 and a screw 22. The screw 22 is carried by an arm 23 extending from a yoke 24 which has a slot similar to the slot 9 and is carried in a groove in the stud 5 similarly to the brush plate 3. The arm 23 has an inwardly turned ledge spaced from the nuts 2i to prevent them from turning. Each of the brush plates 8, as well as the yoke 2 are provided with spring members 25, the ends of which are looped over the corresponding parts as indicated at 26 and 2i. By this construction it will be seen that the yoke and the brush unit plates 3 are laterally movable in their respective slots in the stud 5, as shown in Figure 5.

On the bent or support end 12 of each of the brush unit plates 8, there is mounted, as by a stud 28, a block 29, serving as a pivotal brush, of suitable insulating material, having good wearing qualities. Preferably, the plate 8 is symmetrically positioned with respect to the stud 5 so that the center line of the block 29 is the same distance from the axial center of the stud 5 as the brush I3. The nuts 96 and II, as well as the nut 30 used on the stud 28, are preferably a self-locking type in which a piece of unthreaded material 3!, such as fiber, is locked into the outer surface of the nut so that when these nuts are screwed on, a thread is forced into the fiber or other suitable material, thereby locking the nuts in position on their respective studs.

It will be noted that each of the arms it is provided with a plurality of holes 4| corresponding in number to the brush units carried by the stud together with an additional hole to receive a screw for fastening the terminal $2 connected by a flexible conductor 33, to a brush 34 preferably of the metallic type, which is supported by the arm 23 in contact with the collector ring 3. As shown in Figure 1, there are two brushes 35, one at each end of the yoke M. Since the yoke 24 is resiliently held on the stud 5, each of the brushes 34 acts as a pivot for the other on its collector ring 4. It is to be understood that the collector ring 4 has a conductor or cable attached thereto for conveying the current to the proper part of the circuit with which the regulator or other device is associated.

In Figure 9, 0, illustrates the brush l3 carried by an arm 38 pivoted on a stud 5 positioned a distance 31 from the commutator or track surface 2, according to the conventional or usual style of mounting contact brushes. If, for any reason, due to inaccuracy by the manufacturer, during the movement of the rocker carrying the brush stud 5, this should be carried out a distance 38 from the track 2, then the brush i3 will be tilted or make contact on one corner, as shown in Figure 9, b. Otherwise, if the stud 5 is caused to approach closer to the track surface 2, as illustrated by 39, than in Figure 9, a, then the brush will be tilted as in Figure 9, 0.

By my improved construction of brush rigging-in which the brush unit plate is laterally movable on the stud and rotatable thereon but pivoted on the track surface at a considerable distance from the brush itself, and on the opposite side of the support and guide stud-the objectionable features of conventional mounting, as depicted in Figure 9, are substantially entire- 1y eliminated or the trouble reduced to a minimum, so that the same brush surface may be iaintained over a long period of time.

As shown in several of the figures, the brushes it are formed or have their ends shaped so that the thickness of the brush, where it engages the track, is no wider than one of the bars or conductors, and the resistance of the brush, together with the resistance of the short-cireuited turn, is such that no abnormal current will flow at the instant the brush or brushes pass from one bar to the other.

As shown in Figures 1 and 2, no collector brush is shown in contact with the ring 3, but where the transformer or regulator has a divided or multiple winding, another brush rigging may be used on a stud positioned on the opposite side of the apparatus, with the yoke 24 and associated brush units and parts positioned in reverse direction on the stud 5, the yoke 24 being carried in a groove 48, and having brushes 34 running in contact with the ring 3; or the yoke 2d may be utilized on such a reversely positioned stud and carry only a pair of brushes 34 running on the ring 3 which may be connected in parallel with the ring d.

t is to be noted that the brush unit comprising the plate 8 and the current-conducting brush it, and the pivotal brush "9 of insulating material are positioned on the plate 8 so that they contact with the commutator or brush track in such a manner that the end of the slot 9 will not contact with the reduced portion IQ of the stud 5. Consequently, the spring 25 associated with each plate holds the two brushes of the unit resilient engagement with the brush track so that the center of each brush is movable in an are A on a relatively long radius R.

While I have shown one preferred form of application of my invention, I do not wish to be unduly limited in the interpretation of the appended claims as I believe I am the first to pro vide a brush mounting in which the brush is actually pivoted on the surface or brush track on which it operates, but the brushes may be of any thickness as the brush material or other factors are changed. Fiuthermore, instead of the brush or rider '35 being of insulating material, it is possible to use a brush or rider of conducting material but insulated from the plate 8 or the brush it.

What I claim is:

1. A brush rigging for the purpose described including a mounting stud having a plurality of spaced grooves therein, a slotted yoke positioned in one of said grooves, the yoke having arms extending therefrom in the same direction, each arm carrying a collector ring brush and also having means for carrying brush connectors, brush units, each comprising a metallic plate having a slot therein positioned in certain other of said stud grooves, each plate carrying a currentconducting brush at one end and a brush of insulating material at the other end, the two brushes of the unit being positioned to run on the same brush track, and individual spring means for the yoke and each plate for holding the yoke and brush plates in operative position on their respective brush tracks.

2. A brush rigging for the purpose described including a mounting stud, a yoke transversely carried by the stud and carrying a pair of oppositely disposed current-conveying brushes positioned to run on the same track, the yoke also having at each end an arm for carrying terminal connectors, a plurality of spaced brush units transversely carried on the stud, each unit comprising a plate positioned and resiliently mounted for transitory and pivotal motion on the stud, a brush of current-conducting material carried by the plate at one end and a brush of insulating material at the other end, both brushes being positioned to run on the same track surface.

3. A brush rigging including a support stud, brush units transversely carried by the stud, each unit comprising a plate mounted on the stud for transitory and rotary motion with respect thereto, a current-conducting brush mounted on one end of the plate and a brush of nonconducting material mounted on the opposite end of the plate, resilient means for holding the plate so the brushes run on the same track surface, and means for conveying current away from the conducting brush.

4. A brush rigging including a support stud, brush units transversely carried by the stud, each unit comprising a plate mounted on the stud for transitory and rotary motion with respect thereto, a current-conducting brush mounted on one end of the plate and a brush of non-conducting material mounted on the opposite end of the plate, a yoke carried by the stud and having an arm at each end extending in front of said plate brushes, the arm in front of the brushes of conducting material having terminals thereon for completing connection to said conducting brush, and brushes carried by the yoke arms for conveying current to or from said terminals.

5. A brush rigging including a support stud, brush units transversely carried by the stud, each unit comprising a plate mounted on the stud for transitory and rotary motion with respect thereto, a current-conducting brush mounted on one end of the plate and a brush of nonconducting material mounted on the opposite end of the plate, a yoke resiliently mounted on the stud for transitory and oscillatory motion thereon, the yoke having parts extending in front of the plate brushes and having means for making connections to at least the conducting brushes, and additional brushes carried by the yoke for conveying current to or from the plate brush.

6. A brush rigging including a support stud, brush units transversely carried by the stud, each unit comprising a plate having a current-conducting brush at one end of the plate and a brush of non-conducting material at the opposite end of the plate, the two brushes being disposed so as to simultaneously run on the same surface track, and means for making electrical connection to or from the conducting brush.

7. A brush rigging including a support stud, brush units transversely carried by the stud, each unit comprising a plate having a currentconducting brush at one end of the plate and a brush of non-conducting material at the opposite end of the plate, the two brushes being disposed so as to simultaneously run on the same surface track, and means for making electrical connection to or from the conducting brush, the conducting brush at least being mounted on the plate so as to have a swivel movement for the purpose described.

8. A brush rigging including a support stud, a brush unit carried by the stud, the unit comprising a member extending transversely across the stud for transitory and oscillatory movement thereon, a brush at each end of said member for contacting with a track surface and forming pivotal supports thereon, resilient means for acting on said member to hold the brushes on the track, one brush being conducting while the other is non-conducting, and means for connecting the conducting brush into an electrical circuit.

9. Means for making contact with bars or conductors forming a track surface comprising a support, a member carried by the support, a conducting brush at one end of said member, a nonconducting brush at the opposite end of said member, and resilient means acting on said member to hold both brushes simultaneously and continuously on the track surface, and means for connecting the conducting brush into an electrical circuit.

10. A brush rigging including a support stud, brush units transversely carried by the stud, each unit comprising a plate having a current-conducting brush at one end of the plate and a brush at the opposite end of the plate, the same being insulated from the plate and the currentconducting brush, the brushes being disposed so as to simultaneously run on a track surface, and means for making electrical connection to or from the conducting brush.

11. A brush rigging for a voltage regulator of the circular transformer type having a movable arm and a brush track between a pair of circuit connector tracks located adjacent the brush track including; a metallic stud insulatingly carried by said arm, said stud having annular grooves therein, a plurality of metallic plates having centrally located notches therein to fit in certain of said grooves, each plate having a conducting brush at one end and a non-conducting brush at the other end, a spring carried by the stud for acting on the plate at opposite sides of said stud for holding the plate so both brushes simultaneously engage the brush track, a metallic yoke having a notch located in one of said stud grooves, the yoke having arms extending in front of said brushes and carrying means for making connections to the conducting plate brushes, brushes carried by the yoke arms for engaging one of said connector tracks, and a spring for holding the yoke so its brushes simultaneously engage their track.

12. A brush rigging including a support stud, brush units transversely carried by the stud, each unit comprising a plate resiliently mounted on the stud for transitory and oscillatory motion thereon and having a current-conducting brush at one end of the plate and one brush at the opposite end of the plate, which latter brush, if of conducting material, is insulated from the plate, the said brushes being disposed so as to simultaneously run on a track surface, and means for making electrical connection to or from the conducting brush.

GEORGE ALVIN BREI'IELL, JR. 

